1. Field of the Invention
This invention relates to an abdominal aortic stent. More specifically, this invention relates to an abdominal aortic stent structure which can be easily implanted to reconstruct a vascular flow path.
2. Description of Related Art
The development of stents began since the late '90s to reconstruct normal vascular flow path by inserting stents to separate the aneurysm. It is called endovascular aneurysm repair (EVAR).
Conventionally, in clinical endovascular aneurysm repair practice, a metal wire is inserted from both sides of the femoral artery, and an appropriate stent size would be determined by surgery angiography according to the location, length and influential area of the aneurysm. The stent is then guided to an expected destination through the metal wire. After the membrane wrapped outside the stent is removed, the stent can fully extend to reconstruct a vascular flow path. According to clinical study, the endovascular aneurysm, comparing with conventional surgery, has the advantages of: (1) shorter operative time, (2) smaller amount of blood loss, and (3) shorter recovery time.
Referring to FIGS. 1 to 3, endovascular surgery could be performed via a small wound, which leads to less tissue damage. Also, endovascular surgery causes limited blood loss. Thus, the endovascular surgery has become a trend of modem vascular surgery. On the contrary, conventional abdominal aortic aneurysm surgery is a major vascular surgery, which would generate a 30 to 40 cm abdominal incision from the xiphoid (below the chest) to the top part of the pubic bone. The endovascular surgery can be performed by using a metal wire (1), a membrane (3) and a main stent (2). With the assistance of intra-operative fluoroscopy, the stent can be sent from both sides of the femoral artery into the dilatation position of the abdominal aorta. After the main stent (2) is well positioned, the membrane (3) will be pulled down to have the main stent (2) deploy within the abdominal aortic aneurysm, such that the blood can flow into the main stent (2). If the membrane (3) is continuously pulled down, the main stent (2) will be completely open. Likewise, to connect the main stent (2) to a sub-stent (5), the first step is to put another metal wire (4) through a branch opening (2a) of the main stent (2), and the sub-stent (5) can be guided along the metal wire (4) to an appropriate location. However, sometimes if the blood vessel of a patient has a larger angle, or the branch opening (2a) is hard to be located, it may be difficult to cannulate the metal wire (4) to the branch opening (2a) of the main stent (2), which may increase operation time and even lead to operation related complications.
Therefore, there remains a need for a new and improved stent structure to overcome the abovementioned issues to effectively implant the stent into the abdominal aorta to reconstruct a vascular flow path.